The look of a particular carpet is determined by its construction that may be loop, cut or combinations of loop and cut. In corridors, offices, classrooms, hotel rooms, patient care, and other public areas, loop piles of low, dense construction, tent to retain appearance and resiliency and, generally, provide a better surface for the rolling traffic of wheelchairs and roll carts. Cut pile or cut and loop pile carpets are very good choices for administration areas, libraries, individual offices and boardrooms.
Carpet performance is associated, in part, with pile yarn density, which is defined as the amount of pile yarn per given volume of carpet face. For a given carpet weight, lower pile height and higher pile yarn density typically gives the best performance. The number of tufts per inch and the size of the yarn in the tufts also influence density.
Commercial carpet is primarily manufactured by tufting, weaving, and by fusion bonding processes. Tufted carpets are the most popular, and account for upwards of 95 percent of all carpet construction. The tufting process is generally considered the most efficient and has advanced technology to provide capability for a myriad of patterns and styles.
Tufted carpet generally comprises yarn, a tufting primary into which the yarn is tufted, a secondary backing, and a binder, normally latex, which bonds the yarn, tufting primary and secondary backing together. The yarn is typically nylon and can be in the form of cut pile or loop pile. Cut pile carpet is made of short cut lengths of yarn and loop pile carpet is made of long continuous lengths of yarn. The tufting primary is typically a thin sheet of woven polyester or polypropylene material and the secondary backing is usually jute, woven polypropylene, or polyvinyl chloride (PVC) sheet.
Conventional tufted carpets are made by passing a flexible woven primary backing through a tufting machine having a large array of needles that force the carpet multifilament yarn through the backing where the yarn is restrained by a large array of hooks before the needles are retracted. The backing must accommodate needle penetration without damage. The backing is then advanced a short distance (about 1/10″ for a popular high quality tuft density), and the needles are reinserted through the backing to form the next series of yarn tufts. A large array of cutters may be employed in conjunction with the hooks to cut the tuft loop inserted through the backing to produce a cut-pile carpet. For loop-pile carpets, the tuft loops are not cut.
To assist in stabilizing, stiffening, strengthening, and protecting the tuft base from abrasion, a secondary backing is attached to the underside of the tufted primary backing. The secondary backing may be attached by the same adhesive layer or by the application of more adhesive. To save on costs, inexpensive latex adhesive is most often used. The secondary backing must resist damage during shipping, handling and installation.
Recent EPA requirements for recyclable carpeting require that carpet backings achieve at least 7% recyclable content. Traditional polypropylene type carpet backings do not currently meet this threshold requirement.
There is a need for a tufted carpet construction that is lightweight, dimensionally stable in use, and can be recycled easily to produce useful polymers and meet EPA recyclable content requirements. There is a need for an “all nylon and glass” tufted carpet that is stable to moisture and temperature changes in use. There is a need for a simple inexpensive method of making such tufted carpets. The present invention provides carpet backings for such carpets.